The present invention relates to an air distribution system for an conditioning system and in particular to a system in which, preferably fresh, air is provided from an air supply.
Fan coil systems for moving and circulating air, particularly heating and/or cooling fan coil systems, typically comprise a fan and a coil arranged in a unit in which air is moved by the fan over the coil to a distribution system having ducts for distributing the conditioned air to air conditioned spaces such as offices in an office block building. Return air from the air conditioned offices passes through return ducts and back to the fan coil unit for reconditioning. U.S. Pat. No. 6,213,867 discloses an air handling system in which return air is provided to a heat exchanging unit. U.S. Pat. No. 4,298,164 discloses an air conditioning system in which air from a heat exchanger is provided to a plurality of discharge terminals.
In current buildings it is usually desirable to install a plurality of fan coil units in a separate area remote from the offices to be conditioned. Therefore a dedicated space must be provided for the fan coil units, and this is typically provided by partitioning the office space with, for example, a false wall and false ceiling behind which the fan coil units and ducts are installed. In order for the fan coil units to occupy as small an area as possible, they are usually mounted side-by-side in the dedicated space.
It is particularly desirable to provide fresh air, for example air from outside the building, to the fan coil units for mixing with the recycled conditioned air to provide better indoor air quality in the conditioned office spaces. Fresh air is provided via a fresh air inlet, typically comprising a large duct for conveying air from outside the building to the dedicated fan coil unit space. The ducted fresh air is typically provided to each fan coil unit via an air distribution unit, such as a dedicated suspension box. Therefore, the fresh air supply occupies a significant proportion of the dedicated space, particularly because fresh air from the main fresh air duct has to be supplied to each suspension box by a separate, smaller air duct per box. Therefore the dedicated space required for such an air conditioning system is large, thereby proportionally decreasing the effective area of the building available for office space.
More widespread use of air conditioning systems having fresh air supplies necessitates smaller and more compact systems and therefore it is desirable that the size and distribution of the individual components of the system be kept to a minimum.